Funded Pilot and Feasibility Study #2: Title: Glycosaminoglycan reactivity in lupus as a predictor of disease PI: Fei Shih, M.D., Ph.D. A. Specific Aims Systemic lupus erythematosus (SLE) is characterized by the production of autoantibodies and autoimmune attack of multiple organs. We hypothesized that there are novel targets yet to be discovered for SLE and these may serve as predictors of disease. Based on the highly patterned structure of DNA, we hypothesized that cross reactivity to glycosaminoglycans (GAGs), also a highly patterned structure, may serve as a biomarker for various disease manifestations. This pilot study examines aGAG reactivity in a murine model of SLE and extends aGAG analysis to pediatric patients with SLE with the following specific aims: 1) An unbiased examination of aGAG antibodies in KRN/G7m mice, a murine model of SLE;and 2) Characterize aGAG antibodies in SLE patients and correlation with disease.